215 Church Street
Philadelphia, PA 19106

From https://www.quirkbooks.com/page/about as of 24-Mar-2020:

Quirk Books is headquartered on a charming cobblestone street in the historic Old City district of Philadelphia. Quirk publishes just 25 strikingly unconventional books per year, and every title is a labor of love born out of our passions and obsessions. Always looking to set the next trend, Quirk delivers books and stories that are bold, unprecedented, beautifully designed, and affordable. Some of Quirk’s more popular titles include the best-selling YA series Miss Peregrine’s Home for Peculiar Children, the Edgar Award–winning mystery The Last Policeman, fangirl favorite Geekerella, the legendary Pride and Prejudice and Zombies, and classroom favorite William Shakespeare’s Star Wars—plus children’s books, pop culture titles, cookbooks, art books, gag gifts, and more. Quirk’s books are distributed worldwide by Penguin Random House and available wherever books are sold.